I have read the threads on square rooms, but unfortunately only for the first time this evening. The attached shows the layout of the room. it is 16.89' wide, 16.36' long (deep) and is 7.87' high at the back of the room, racking up to 12.13' at the front of the room.

The structure is on beams with timber construction joists / bearers being 3.6' from ground level (old concrete slab).

I am in constuction stage, timber frame built, but no sheeting yet. So I have some freedom to make some changes. The right wall is brick (back of original house), the other 3 sides are going to be cladded.

Window on the LHS (1800mm high window wall.)

The question really is: If I move the Sub to beside the future couch (where I show a MUS (music cabinet) will I dramatically improve the room.

If I build a nib wall to the right og the right speaker (I have sketched the idea in green, would that make any difference / improvement. I could put one to the right of the couch as well.

Ok, so the Nib wall will not rectanglize (if that is a word ) the room.

So in summary, build as is, then bass traps in corners. You have a distributor in Australia which is great.

Am I correct with the maths and your software, that the height of the room for calculations is 2.4m to 3.6m rake is an average of 3.0m then I add the 1.1m for the Floor (ply flooring) down to the Slab below (house is on piers onto an old carport slab 1.1m below)

Also, is their a particular material for the window wall (1800mm high x 3000mm long) which will help. Should it be a heavy material or light, so the Bass is dampened.

An interior wall will most likely Only modify the specular reflections above the modal frequencies.

Unless the wall is massive (as in near identical to the exterior walls - assuming they are massive), the exterior walls will still determine the modal distribution of the interior energy, and the interior wall will do nothing to substantially modify the modal behavior, which due to the square room with near identical dimension has multiple surfaces reinforcing the same modal standing wave frequencies and thus exacerbating the situation.

Thus, you must still determine a mixed strategy based upon listener placement relative to modal peaks and nulls, subwoofer placement, tuned resonant pressure based traps, and passive velocity based porous traps and the limited judicious use of EQ.

Thus, unless you are intending to build a full sized interior wall (as part of a larger strategy) in order to modify the symmetrical specular behavior in the room such that the primary listening position could be offset from the geometric center of the room and away from the modal nulls defined by the more massive exterior boundaries - a good strategy commonly employed in professional and studio deigns to avoid the modal nulls if you can afford the 'loss of real estate' - the wall will not help with the LF modal issues.

Am I correct with the maths and your software, that the height of the room for calculations is 2.4m to 3.6m rake is an average of 3.0m then I add the 1.1m for the Floor (ply flooring) down to the Slab below (house is on piers onto an old carport slab 1.1m below)

Calculators like my own Graphical Mode Calculator are meant to help design a new space that's not yet built. For an existing room, measuring will tell you exactly where the problem frequencies are, with more accuracy. But even that isn't usually needed. No matter what you measure, the solution is more or less the same: bass traps, absorbers at reflection points, and optionally diffusers.

Quote:

Should it be a heavy material or light, so the Bass is dampened.

The best walls are lightweight because they let bass pass through to the outside. Lighter walls can also give some bass trapping as they vibrate in sympathy. This absorbs bass energy, though the walls need insulation inside for this to work well.

Hi Guys, I thought of something and would love your input. The Right Wall - existing back of the house, it hasn't been fitted with ferring channel yet, so what if I built that wall at an angle, so back is the 5150mm as shown, but on the screen wall it is is 300 - 600mm more narrow. Taking into account the ceiling is raked, does that solve many of the probelems

If the wall is insufficiently massive to function as a modal boundary (which is the most likely scenario...), then all it will do is screw with the specular reflections above the modal frequencies without any significant effect on the modal distribution which will still be determined by the more massive exterior boundaries.

If the angled wall is sufficiently massive to modify the low frequency modal energy, all it will do is result in a more complex modal distribution requiring still more effort to measure and map said distribution.

Multiple subs is your best bet deployed in mode canceling arrangements. Above the sub region youll need some serious bass trapping, stuff that is effective down to the sub crossover frequency.

Want to learn about home theater design and acoustics? Read our blog.Company: Acoustic Frontiers- design and creation of high performance home theaters for discerning audio/video enthusiasts.Certifications: HAA Level I & II, THX Video Level I & II, CEDIA EST I & II.AVS Projects: Too many to show in my signature - see here for the master list.

As the saying goes, there are lies, utter lies and statistics. Simulations involving just a few possibly-cherry-picked examples prove nothing.

IMO you are over-thinking the problem. If you want to know what your room does, do some measurements of your room. I know about the long-standing audiophile tradition of spending $1,000s on equipment and refusing to pay even one dollar ($1) for test equipment to see how that equipment is working. Time to break that mold!

Quote:

Anyone can confirm this? Will having 2 subwoofers in a cubed room make a good room?

These are the results of a study from Harman that talks about the possible benefits of using multiple subwoofers.

Yes, it's the worst shape possible. I can't speak for the graphs on that web site, but you need to see up to 300 Hz. Multiple subs might help, but the main problem is strong resonances that require bass traps to tame.

As Nyall said in the post right before your's: the subs can be set up in a mode cancelling arrangement to mitigate some of the bass problems in a square/cube shaped room. But that only works up to the crossover point. For bass above that point, you can't re-arrange your speakers for mode cancelling because you need to place them for good soundstage and proper imaging. Hence Nyall's recommendation for "serious bass trapping" down to the crossover point.

Yes, it's the worst shape possible. I can't speak for the graphs on that web site, but you need to see up to 300 Hz. Multiple subs might help, but the main problem is strong resonances that require bass traps to tame.
--Ethan